h1 class=”calibre8″>11 Subaxial Cervical Spine Trauma in the Pediatric Patient

Catherine A. Mazzola and Nicole Silva

Keywords: cervical, child, children, injury, instability, pediatric, spinal, spine, subaxial, trauma

11.1 Introduction

Due to the incomplete maturation of the child’s spine, pediatric subaxial cervical injury (PSCI) in children is somewhat different than its adult counterpart. The anatomical and developmental characteristics of the pediatric spine impact the clinical presentation, imaging characteristics, patterns of injury, and treatment. ¹ In the pediatric population, subaxial spinal injuries are mostly due to motor vehicle accidents, pedestrian struck by motor vehicles, and sports-related injuries. ^1,2 Although there have been major efforts to prevent these injuries, in the development of better car seat technology, safety belts, helmets, and education programs, injuries still occur. In the ambulatory field, immobilization and stabilization of the cervical spine are paramount after airway, breathing, and circulation issues have been addressed. Transportation to a trauma center and appropriate imaging, followed by a detailed neurological examination take precedence. Identification and treatment of subaxial treatment should follow best clinical practice guidelines.

11.2 Embryology, Anatomy, and Development

The upper cervical spine consists of the C1 atlas which is formed by three ossification centers and the C2 axis with five primary and two secondary ossification centers. ^1,3 Development of the lower vertebral bodies begins with three primary ossification centers, with one in the body and two laterally in the neural arches at each vertebral level, and secondary ossifications centers at the superior and inferior epiphyseal ring. ³ The morphometric and growth characteristics of the pediatric cervical spine have been described. In the midsagittal plane, 50% of cervical spinal growth occurs before the age of 9 years with spinal height continuing to increase in males, tapering off at the age of 17. ⁴ In females, 66.8% of the height development occurs before 9 years of age. Girls stop growing in height at an average age of 14 years. ⁴ In children, the head-to-body ratio is larger than it is in adults creating instability with a higher center of gravity and fulcrum of the neck. ¹ This fulcrum of movement shifts as the child matures, moving from C2 to C3 as an infant, to C4–C5 at the age of 5 or 6 years, and C5–C6 during adolescence and adulthood ⁵ (▶ Table 11.1 and ▶ Table 11.2).

11.3 Biomechanics and Morphometrics of the Pediatric Subaxial Spine

The subaxial cervical spine includes the vertebral levels of C3 to C7 (▶ Fig. 11.1). The immature cervical vertebra has a small body attached to the lamina with short, narrow pedicles and spinal processes that are underdeveloped and bifid. The transverse processes of the C3 to C6 vertebral levels are small and short with foramen transversarium. Although initially more wedge shaped than adult vertebrae, the more mature C3 and C4 levels resemble a typical cerebral vertebral body in size and structure, but the C7 can be considered a transitional vertebra. It resembles the thoracic vertebral body in size with a large posterior spinal process, but with a configuration more similar to a cervical vertebra. In addition, the transverse process of C7 is larger and occasionally will not have a foramen transversarium. ^4,6

It is very important to consider the hypermobility and ligamentous laxity of the immature subaxial spine during development. ³ The articular processes will have a more axial position, with vertebral bodies that are wedged-shaped, contributing to increased movement of the spine. ⁵ This is especially noted in children under the age of 8 years. ⁵ The facet joints in the pediatric subaxial spine are more horizontally oriented allowing for easier subluxation. ⁶ The anterior longitudinal ligament (ALL) and posterior longitudinal ligament (PLL) are draped over the anterior and posterior vertebral body surfaces, respectively, from their attachment at C1 all the way to the sacrum. ⁵ Although the ALL and PLL provide stability to the subaxial spine, these ligaments are lax and underdeveloped in children increasing flexibility. ⁵ The uncovertebral joint does not develop completely until the age of 8 years. ⁵ Hypermobility and decreased resistance to injury are due to multiple factors that affect the immature pediatric spine. ^5,6

11.4 Epidemiology and Patterns of Injury

11.4.1 Demographics and Epidemiology

According to the Centers for Disease Control (CDC), motor vehicle accidents are the leading cause of death in children up to the age of 14 years. ⁷ Recent data analyses of all pediatric trauma admissions, from the Kids’ Inpatient Database (KID), suggest that between 2000 and 2012, the prevalence of pediatric cervical spine injury (PCSI) was 2.07% and the mortality rate was 4.87%. ² The most frequent cause of pediatric cervical spine trauma was motor vehicle accidents which accounts for about 57.51%. ² Cervical spine injury in pediatric injuries are more common than thoracic and lumbar spinal injuries, accounting for about 60 to 80% of all spinal injuries. ⁸ The most common cause of pediatric spine injury, from most to least prevalent, are motor vehicle accidents including pedestrian struck by a motor vehicle, followed by falls, sports, diving accidents, firearms, and child abuse. ^1,2,9 Motor-vehicle-related trauma is more common in younger children while older children are more likely to suffer from sports-related injuries. ¹⁰ While in infants, the upper part of the cervical spine is most commonly injured; in school-aged children, the lower level of the subaxial spine is more frequently injured because of caudal shift of the fulcrum of the movement of the spine in older childhood. ^1,5,10 Finally, there are many connective tissue disorders such as Down syndrome, Marfan syndrome, and other disorders that predispose children to subaxial cervical spine injuries. ¹

11.4.2 Types and Patterns of Injury

Spinal Cord Injury/SCIWORA

Spinal cord injury (SCI) is more common in younger children due to increased ligamentous laxity. ^3,5 Treatment of SCI in children is very similar to that of the adult SCI, with extent of recovery limited to degree of initial neurological impairment. ³ The diagnosis of SCI without radiological abnormality (SCIWORA) is less common with the advent of improved magnetic resonance imaging (MRI) techniques. When a child presents with a clinical deficit, there is usually an abnormality found on imaging. It is rare that a child presents with neurological findings without any evidence of spinal column or SCI.

Vascular Injury

Vascular injury should be suspected in PCSI, especially when neurological deficits or fracture through the foramen transversarium are present. The vertebral artery travels through the foramen transversarium of the cervical vertebrae. ⁶ Vascular injury in the cervical spine can cause brain stem or spinal cord infarct, hematoma, and/or hemorrhage. ⁵ Concomitant craniocervical arterial dissection (CCAD), is a life-threatening injury that may occur with any cervical trauma. ³ The gold standard diagnostic study for evaluation of vascular injury is the cervical angiogram. Magnetic resonance angiography (MRA) or computed tomography angiography (CTA) may be carried out to either rule out or intervene in evaluate vascular injury in PCSI. It is important to be cognizant of the very real risk of vascular injury in children with increased risk of cervical mobility, ligamentous laxity, and subluxation. ³ Vertebral artery dissection, disruption, and occlusion have been well described.

Ligamentous Injury and Subluxations (Without Fracture)

Children with immature spinal development are more prone to ligamentous injury. ¹⁰ Under the age of 12 years, normal physiological ranges of motion of the cervical vertebrae can be up to 4 mm from neutral in C2 to C4, and about 3 mm from neutral position in levels below C4 (when comparing neutral position to maximal flexion). ¹¹ Subaxial pseudosubluxation, with minimal subluxation (typically C2–C3 or C3–C4), is common in children and is often noted on radiographic imaging between C2 to C4 as up to 4 mm of movement from neutral. ³ This should not be mistaken from a true subluxation for patients under the age of 8 years, which is a movement of greater than 4.5 mm between C2 and C3 or C3 and C4 or greater than 3.5 mm at any other lower level. ⁵ Another common way to measure ligamentous injury is measuring the degree of angulation between adjacent vertebra, which should be less than 7 degrees. ¹¹ Children with X-ray evidence of true subluxation should be placed in a hard collar, and MRI should be obtained with and without intravenous contrast to assess integrity of cervical ligaments. If there is ligamentous injury or inflammation, stabilization (temporary in collar, or permanent, internal stabilization) may be needed.

Bilateral Facet Fractures/Dislocations

Facet dislocations are posterior column injuries and they represent the second most common injury pattern in PCSI. ¹¹ Bilateral facet dislocation occurs when there is flexion-distraction or rotation-compression injury. Typically, plain radiographs are sufficient to rule out facet dislocation, but CT scan may be needed to rule out subtle fractures, and MRI may be necessary to evaluate ligamentous and/or SCI. ¹¹ Children with bilateral facet fractures and dislocation are likely to present with neurological findings.

Unilateral Facet Fracture

Unilateral facet fractures are the most frequently missed cervical spine injury on plain X-rays and they vary with severity based on the stability of the patient’s subaxial cervical spine. ¹¹ CT imaging is better for the evaluation of unilateral facet fractures, but they may also be identified on MRI. They may occur with flexion, distraction when in rotation, and they lead to subluxation and monoradiculopathy that improves with traction. Most facet dislocations occur within the subaxial spine.

Single-Level Disc/Teardrop Injury

Cervical teardrop fractures are unique injuries that pose an unstable condition of possible neurological deficits due to posterior displacement of the fractured vertebra and impingement on the spinal cord. ¹² This injury will cause widening of the interlaminar and interspinous spaces with kyphotic deformity seen on imaging. ¹² It is a rare injury in children and usually results from traumatic flexion or extension. ^13,14 Most of these injuries will require immobilization and stabilization.

Single-Level Burst Fracture

Burst fractures are anterior column injuries due to axial loading and compressive forces transmitted through the annulus fibrosus and onto the neighboring vertebral bodies. ¹¹ These fractures typically occur with a forced forward flexion movement that impairs the posterior stabilization mechanism. ¹⁵ Single-level burst fractures may occur with or without neurological injury. Retropulsed bone fragments may need to be removed through an anterior approach, followed by anterior and possibly posterior stabilization.

Single-Level Compression Fracture

Compression fractures are very similar to burst fractures and can result in a significant instability of vertebral height loss and spinal cord stenosis. ¹⁵ Mild compression fractures typically occur without neurological sequelae, but severe compression fractures may be associated with neurological deficits. Rigid cervical orthosis may be utilized. Patients should be carefully followed to rule out progressive kyphosis and instability.

Single-Level Vertebral Fractures (Other Types)

Fractures are the most common type of injury in subaxial cervical spine and risk of fracture increases with age of the child. ² Single-level vertebral fractures are most commonly the result of sports-related injuries in older children, and the patterns of fracture are similar to those seen in adult cervical fractures. ¹⁶

Transverse process fractures

Although rare, transverse process fractures may cause painful radiculopathies. They are not unstable and do not require bracing. Transverse process fractures result from an extreme rotation or lateral bending movement.

Spinous process fractures

Also known as a “clay shoveler fracture,” this type of fracture occurs when the end of the spinous process is broken off by a physical force or when paraspinal muscles pull so hard on the spinous process, that it breaks off part of the spinous process. Spinous process fractures may result from severe flexion or extension or a direct blow to the neck. Spinous process fractures may be indicative of ligamentous injury, so rigid orthoses should be utilized until MRI can be done. Immobilization and stabilization for a few weeks in a hard collar may be adequate treatment.

Multilevel Burst and Other Fractures

Complicated burst and other fractures are the result of high-energy trauma and must be treated with the extreme caution. These children typically present with neurological deficits. Cervical immobilization and stabilization are crucial in the treatment of these injuries. Spinal cord decompression and cervical spine fusion through an anterior, posterior, or combined approach may be indicated.

11.5 Prehospital Management

Management of the ABCs (airway, breathing, and circulation) followed by immobilization and stabilization of the spine are the most important considerations for children with spinal injuries. Immobilization of the cervical spine in a size-appropriate manner is essential. Over the age of 8 years, backboard and cervical collar immobilization should be used. However, it is recommended that a standard backboard should be modified for patients under the age of 8 years due to their large head-to-body ratios, which causes flexion of the cervical spine in the supine position. ¹¹ The patient’s torso may be elevated in order to maintain a neutral cervical alignment. ¹¹ Children under the age of 8 years should be immobilized by building up the torso on a regular backboard. ¹¹ Infants cannot be placed in a cervical collar and should be stabilized with sandbags or foam head blocks, which are secured at both sides of the head and taped to a modified backboard. ^10,11

11.6 Clinical Examination

Clinical examination of the pediatric trauma patient is challenging due to many reasons. It is extremely important to get a thorough history of the patient’s injury. Mechanism of injury often indicates the severity of trauma expected. When the history does not correlate with the physical or radiological findings, the clinical history may be suspect or child abuse may be considered. A complete physical examination is important. Evidence of any obvious lacerations, abrasions, and/or ecchymoses are important to document. Battle sign, or ecchymosis around the mastoid bones, bruising around the neck, or cervical hematomas are ominous signs. Cervical collar and backboard immobilization should be utilized until a patient with a suspected injury is cleared by X-ray imaging. It is crucial to perform an age-appropriate, comprehensive neurological exam as deficits correlate well with PCSI. ³ Presenting symptoms may be neck pain and rigidity, altered mental status, focal neural deficits, torticollis, numbness, radicular pain, or weakness. ^1,10

Although there are no comprehensive pediatric screening guidelines, there are several adult guidelines that are commonly used in both the United States and Canada by medical professionals. It is difficult to get a traumatized child to cooperate and complete a full neurological examination, especially when the child is upset, anxious, and afraid. ¹⁰ The National Emergency X-Radiography Utilization Study (NEXUS) identifies five criteria which stratify patients based on the likelihood of having sustained injury to the spinal cord including

1. 
   

   No midline cervical tenderness.

   
   
2. 
   

   No focal neural deficits.

   
   
3. 
   

   Normal alertness.

   
   
4. 
   

   No intoxication.

   
   
5. 
   

   No painful distracting injury. ^10,17

Children who meet all five criteria are unlikely to have PSCI. ^10,15

In comparison, the Canadian “C-Spine Rule” recommends that clinicians ask following three questions:

1. 
   

   Is there any high-risk factor present that mandates radiographic assessment (i.e., a dangerous mechanism of injury)?

   
   
2. 
   

   Is there any low-risk factor present that allows for the safe assessment of range of motion (i.e., is the patient able to ambulate independently)?

   
   
3. 
   

   Is the patient able to actively rotate his or her neck 45 degrees to the left and right?

A negative answer to the first question and/or affirmative answers to the last two questions rules out the possibility of cervical spine injury in adult patients with a high specificity. ^10,18

The National Institute for Health and Care Excellence (NICE) Guidelines have identified three high-risk inclusion criteria:

1. 
   

   Age 65 years or older.

   
   
2. 
   

   Dangerous mechanisms of injury (fall from a height of greater than 1 m or five steps, axial load to the head, rollover motor vehicle accident, ejection from a motor vehicle, accident involving motorized recreational vehicles, bicycle collisions, horse riding accidents).

   
   
3. 
   

   Paresthesia in the upper or lower limbs. ¹⁹

In pediatric trauma patients, evaluation of clinical and neurological status is difficult. Adult guidelines are not applied to pediatric patients with SCI and thus, we recommend using a combination of these guidelines with special attention to the maturing spine of the child. ²⁰ For children under the age of 2 years, we recommend a high index of suspicion for occult PSCI. ²⁰ In summary, PCSI should be considered if any of the following criteria are met ¹⁰:

1. 
   

   After a fall from 10 feet or greater (or body height if < 8 years).

   
   
2. 
   

   Motor vehicle accident (MVA).

   
   
3. 
   

   Glasgow Coma Scale (GCS) < 14.

   
   
4. 
   

   Neurological deficit.

   
   
5. 
   

   Significant head, face, or neck trauma.

   
   
6. 
   

   Neck pain or torticollis.

   
   
7. 
   

   Distraction injury or intoxication. ¹⁰

PSCI algorithms are being continuously developed for attainment of the best possible outcomes in these cases. ²⁰

11.7 Diagnostic Imaging and Indications

There is significant controversy in the literature regarding the proper use of imaging in pediatric patients with subaxial injuries. Exposure to radiation is a concern in younger patients. Imaging of PSCIs should be conducted in unison with clinical and neurological findings.

11.7.1 X-ray Imaging of the Subaxial Cervical Spine in Children

Plain radiographs are often obtained shortly after initial assessment, if PSCI is suspected. ^8,10 X-rays are useful for the rapid, early detection of severe injuries such as cervical spine fractures and subluxations (▶ Fig. 11.2 and ▶ Fig. 11.3). In an intact and cooperative child, negative clinical and neurological examinations combined with negative cervical spine imaging studies rule out cervical spine injuries. ²¹ X-ray imaging may help identify subtle injuries that mandate MRI in PSCI. ²² It is recommended that children who do not meet NEXUS criteria should receive anteroposterior and lateral cervical spine X-rays. ^5,23 However, recent studies have questioned the utility of flexion, extension, and oblique views unless there is postinjury spinal tenderness persistent in a neurologically intact pediatric patient. ^8,10

Related posts:

Traumatic Atlantoaxial Rotatory Fixation Cranioskeletal Traction for the Management of Trauma to the Cervical Spine Trauma in Patients with Rheumatoid Arthritis of the Cervical Spine Penetrating Injuries to the Cervical Spine Clinical Trials Update: Where Do We Go from Here? Initial Assessment (Including Imaging) of Cervical Spinal Cord Injury

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